Six of Qualcomm Inc.’s directors, including Chief Executive Steve Mollenkopf, failed to win support from a majority of the company’s shares Friday, a significant protest vote that signals investor discontent after the chip-making giant successfully rebuffed a hostile takeover from Broadcom Ltd.

At the company’s annual meeting in San Diego, just 40% to 50% of the total shares outstanding were voted in favor of the six directors, with the other four getting more than 50%, according to a person familiar with the count.